Add native support for Swiss projections

This PR adds native support for the two projections used in Switzerland, EPSG:2056 and EPSG:21781.

Note that when the custom build tool is created this will not add any extra bytes for people who do not use these projections.

The reasons for adding native support for these projections rather than using Proj4js are:

* There are fast, reasonably accurate (1-3m) and direct transformations between EPSG:2056, EPSG:21781 and EPSG:4326 that Proj4js does not include.
* Proj4js does not reveal validity extent, point resolution, or axis order.